A kind of polytetrafluoroethylhollow hollow fiber membrane and preparation method thereofTechnical field
The present invention relates to polytetrafluoroethylhollow hollow fiber membranes and preparation method thereof to be particularly suitable for membrane distillation for separating.
Technical background
Polytetrafluoroethylene (PTFE) since its use temperature range is wide, while have excellent chemical stability, low frictional properties and absolutelyEdge thermal insulation not only has excellent chemical stability, thermal stability, electricity using the separation membrane material that polytetrafluoroethylene (PTFE) is prepared as raw materialInsulating properties also has the characteristics such as outstanding waterproof, radix saposhnikoviae, moisture-inhibiting, ventilative and charge stable storing.It is in manufacture protective garment, bagFormula deduster, architectural lighting etc. have shown excellent performance.National Palaestra " Bird Nest ", dome in thousand of Britain etc.A large amount of PTFE microporous barriers are used.However that there are still flux in the application is small, filtering essence for current microporous teflon membranThe disadvantages of low, fenestra is easy to pollute, at high cost is spent, the application of industrialized production is had not been achievable.
Inventor has been devoted to the research to the structure of high molecular material, and the control and modification to material structure can getThe high molecular material of different characteristics and function.However polytetrafluoroethylene film relation be- tween structure and properties are not made clear of at presentIt is thorough, as separation accuracy is difficult to take into account with treatment effeciency；With accurate microstructure, it is easy to impaired, service phase is short, use costIt is high；Polytetrafluoroethylene (PTFE) physical and chemical performance is stablized, and structure control, performance improvement realize difficulty is big, and difficulty of processing is big etc..
Summary of the invention
The polytetrafluoroethylhollow hollow fiber membrane that the purpose of the present invention is to provide a kind of service phases is long, treatment effeciency is good.
The purpose of the present invention is what is realized by following measures:
A kind of polytetrafluoroethylhollow hollow fiber membrane has the pore structure of three-dimensional perforation, there is transforaminal, hole on the stem of holeAperture is 200 ± 100nm, and stem diameter is 125 ± 75nm, 45 ± 25nm of transforaminal aperture；The porosity of hole is 80 ± 10%, stemThe porosity in hole is 30 ± 15%；The total surface area of the stem, stem area: transforaminal area=1-15:1；Internal diameter is not more than 2mm.
The film is during the Selective Separation for substance, when one such or different kinds of molecules is passing through material tableWhen face and/or inside, the microstructure of molecule will receive itself and the effect of material and the influence of bond structure, to affect objectThe percent of pass and throughput of matter, the microstructure of another aspect material also will receive influence, to influence material separation tower, clothesLabour phase etc..So both ensure that separate substance by efficiency and throughput, combine the utilization rate of material.Transforaminal is on stemDistribution situation be one of key factor.
Preferably, in order to further increase correlated performance, the polytetrafluoroethylhollow hollow fiber membrane, hole aperture is 200-250nm, stem diameter 80-120nm, transforaminal aperture 30-45nm；Wherein the porosity of hole is 75-85%, the porosity of transforaminalFor 25-30%；The total surface area of the stem, stem area: transforaminal area=8-12:1.
100-200 μm of the film thickness of above-mentioned hollow-fibre membrane.Internal diameter is 0.2-2mm.
Polytetrafluoroethylene (PTFE) has stable inert physical and chemical performance, and processing is not easy, especially for its microstructureControl and holding are even more industry problem.The present invention provides the preparation sides of the polytetrafluoroethylhollow hollow fiber membrane of above-mentioned special constructionMethod, using method of electrostatic spinning, including the preparation of spinning lotion, spinning, preforming, sintering, temperature-control pressure-control is continuously burnt in the sinteringKnot；It is described it is preforming be that the precursor film for obtaining spinning is wrapped on cylinder branch hold mode formation doughnut form；Winding circle numberControllable film thickness.
The present invention provides the preparation method with the PTFE high molecular material of above structure, comprising the following steps:
(1) spinning solution prepares: polytetrafluoroethylene (PTFE) is added in the polyvinyl alcohol homogeneous solution soluble in water for obtaining 14-15% concentration(PTFE) lotion (55-60%), so that PTFE and polyvinyl alcohol mass ratio are 2-3:1；
(2) spinning: electrostatic spinning is carried out using high-voltage electrostatic spinning apparatus, obtains even fiber precursor film；Spinning voltage15 ~ 20kV, 12 ~ 30cm of distance；
(3) preforming: the precursor film that spinning is obtained is wrapped on cylinder branch hold mode of the outer diameter no more than 2mm and forms doughnutForm；
(4) be sintered: 1. under a high vacuum (3-5Pa) with 5-6 DEG C/min from room temperature to 98-103 DEG C, and keep temperature andPressure 25-30min；2. being filled with nitrogen to pressure value in 120-180s is greater than 70kpa no more than 75kpa, while with 4-5 DEG C/minIt is warming up to 375-380 DEG C of temperature value, and keeps 10-12min in the case where pressure value is greater than 70kpa no more than 75kpa, 375-380 DEG C；3. after heating, keeping vacuum to cooling to 50-100Pa.
Above-mentioned spinning lotion is prepared as preparing high molecular polymerization composition granule, the high molecular polymer using emulsion polymerizationGrain average grain diameter is 15-80nm.This makes material have better stem, pore size, optimizes the property such as impact flexibility, ageing resistanceEnergy.
Porosity=hole porosity of material+(porosity of 1- hole) * transforaminal porosity.
Beneficial effect
1. the present invention improves the treating capacity that material carries out substance selection by the improvement to polytetrafluoroethylene (PTFE) semi-permeable material structureIt is high with the selection separative efficiency of the persistence of selection separating property, material, excellent effect is selected, and the service phase of material is long.
2. the super-hydrophobic polytetrafluoroethylfiber fiber film that the present invention is coupled hardness with softness has stable and firm fibre morphologyWith transforaminal structure, collapsing for bone skeleton is prevented.
3. effective membrane area of unit volume of the present invention is big, easy to clean, structure is simple, easy to operate.
Specific embodiment
The present invention is specifically described below by embodiment, it is necessary to which indicated herein is that the present embodiment can only be usedIn invention is further explained, it should not be understood as limiting the scope of the invention, the people that is skilled in technique in the fieldMember can make some nonessential modifications and adaptations according to the content of aforementioned present invention.
Embodiment 1
A kind of polytetrafluoroethylhollow hollow fiber membrane has the pore structure of three-dimensional perforation, there is transforaminal, hole on the stem of holeAperture is 200 ± 100nm, and stem diameter is 125 ± 75nm, 45 ± 25nm of transforaminal aperture；The porosity of hole is 80 ± 10%, stemThe porosity in hole is 30 ± 15%；The total surface area of the stem, stem area: transforaminal area=1-15:1；It is 100-200 μm of film thickness, interiorDiameter is 0.2-2mm.
Stem surface area graphical analysis: with scanning electron microscope (SEM photograph amplifies 10000-50000 times) shooting materialPhoto.The photo (the TV image processor TVIP- of Japanese Avionics company production is scanned with image processing facilityThe TV image processor that 4100II, Latock system engineering company provide) stem and transforaminal are separated to obtain stem and transforaminal figureAs handling image by software, obtaining respective area, stem area and transforaminal area-graph can be calculated as the ratio between gross area.
Aperture, stem diameter, porosity are detected using nanometer CT.
The preparation method of this polytetrafluoroethylhollow hollow fiber membrane, according to the following steps:
(1) spinning solution prepares: polytetrafluoroethylene (PTFE) is added in the polyvinyl alcohol homogeneous solution soluble in water for obtaining 14-15% concentration(PTFE) lotion (55-60%), so that PTFE and polyvinyl alcohol mass ratio are 2-3:1；
(2) spinning: electrostatic spinning is carried out using high-voltage electrostatic spinning apparatus, obtains even fiber precursor film；Spinning voltage15 ~ 20kV, 12 ~ 30cm of distance；
(3) preforming: it is that doughnut shape is formed on 0.2-2mm cylinder branch hold mode that the precursor film that spinning is obtained, which is wrapped in outer diameter,State；
(4) be sintered: 1. under a high vacuum (3-5Pa) with 5-6 DEG C/min from room temperature to 98-103 DEG C, and keep temperature andPressure 25-30min；2. being filled with nitrogen to pressure value in 120-180s is greater than 70kpa no more than 75kpa, while with 4-5 DEG C/minIt is warming up to 375-380 DEG C of temperature value, and keeps 10-12min in the case where pressure value is greater than 70kpa no more than 75kpa, 375-380 DEG C；3. after heating, keeping vacuum to cooling to 50-100Pa.
160-170 ° of resulting materials hydrophobic angle.Gained PTFE material is subjected to membrane distillation at normal temperature: hyaluronic acid it is pureChange, crystallization, is adapted to industrial excellent properties and effect.It can obtain the product better than the drug standards.Membrane distillation is logicalAmount > 22L/m2H, rejection are stablized 99% or more, are carried out continuously membrane distillation 3-5 months, flux drops to former flux 70-75%, material color is pure white after cleaning, and for flux recovery before 95% or more, service phase is 3-5.
Embodiment 2
A kind of polytetrafluoroethylhollow hollow fiber membrane has the pore structure of three-dimensional perforation, there is transforaminal, hole on the stem of holeAperture is 200-250nm, stem diameter 80-120nm, transforaminal aperture 30-45nm；Wherein the porosity of hole is 75-85%, stemThe porosity in hole is 25-30%；The total surface area of the stem, stem area: transforaminal area=8-12:1.Internal diameter 0.3-1.4mm, film thickness120-150µm。
163-172 ° of resulting materials hydrophobic angle.Gained PTFE material is subjected to membrane distillation at normal temperature: hyaluronic acid it is pureChange, crystallization, is adapted to industrial excellent properties and effect.The product better than the drug standards can be obtained, water is reachableMedical used injection water standard.Flux of membrane distillation > 24L/m2H, rejection are stablized 99% or more, are carried out continuously membrane distillation 3-5Month, flux drops to former flux 70-75%, and material color is pure white after cleaning, and flux recovery is before 95% or more, service phaseIt is 3-5.
Embodiment 3
A kind of polytetrafluoroethylhollow hollow fiber membrane has the pore structure of three-dimensional perforation, there is transforaminal, hole on the stem of holeAperture is 240nm, stem diameter 100nm, transforaminal aperture 36nm；Wherein the porosity of hole is 79%, and the porosity of transforaminal is26%；The total surface area of the stem, stem area: transforaminal area=9:1.Internal diameter 1mm, 125 μm of film thickness.
169 ° of resulting materials hydrophobic angle.Gained PTFE material is subjected to membrane distillation: the purifying of hyaluronic acid, knot at normal temperatureCrystalline substance is adapted to industrial excellent properties and effect.The product better than the drug standards can be obtained, water reaches medical injectionPenetrate water supply standard.Flux of membrane distillation > 24L/m2H, rejection are stablized 99% or more, are carried out continuously membrane distillation 3-5 months, lead toAmount drops to former flux 70-75%, and material color is pure white after cleaning, and before 95% or more, service phase can be grown flux recoveryUp to 3-5.